Electro static discharge (ESD) is a common undesirable phenomenon in a semiconductor device. In a thin film transistor (TFT), the electro static discharge may lead to dielectric breakdown, a threshold voltage shift of the thin film transistor or a short circuit between a gate and a source and drain of the thin film transistor. For a thin film transistor liquid crystal display (TFT-LCD), during operations of the thin film transistor liquid crystal display, when static charges on a data line or a gate line accumulate to a certain extent, breakdown of an insulation layer for separating the gate and the source and drain of the thin film transistor may occur, resulting in the short circuit between the source and the gate of the thin film transistor, and moreover, even no breakdown occurs in the insulation layer for separating the gate and the source and drain of the thin film transistor, the accumulated static charges may lead to a voltage difference between the gate and the source of the thin film transistor, resulting in the threshold voltage shift of the thin film transistor and changes of performance characteristics of the thin film transistor.
In order to reduce influences of the electro static discharge on the thin film transistor liquid crystal display, an electrostatic discharge circuit is usually used to release a high voltage static electricity produced during a manufacturing process or a working process of the thin film transistor liquid crystal display. However, in prior art, when the electrostatic discharge circuit is turned off, a leakage current is easily generated so that a quality of a picture displayed by the thin film transistor liquid crystal display is affected.
Since the thin film transistor, the data line, the gate line etc. of the thin film transistor liquid crystal display are generally provided in an array substrate of the thin film transistor liquid crystal display, a problem to be solved urgently is to design an array substrate capable of releasing static electricity well.